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Hodapp SJ, Gravel N, Kannan N, Newton AC. Cancer-associated mutations in protein kinase C theta are loss-of-function. Biochem J 2024; 481:759-775. [PMID: 38752473 DOI: 10.1042/bcj20240148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 06/11/2024]
Abstract
The Ca2+-independent, but diacylglycerol-regulated, novel protein kinase C (PKC) theta (θ) is highly expressed in hematopoietic cells where it participates in immune signaling and platelet function. Mounting evidence suggests that PKCθ may be involved in cancer, particularly blood cancers, breast cancer, and gastrointestinal stromal tumors, yet how to target this kinase (as an oncogene or as a tumor suppressor) has not been established. Here, we examine the effect of four cancer-associated mutations, R145H/C in the autoinhibitory pseudosubstrate, E161K in the regulatory C1A domain, and R635W in the regulatory C-terminal tail, on the cellular activity and stability of PKCθ. Live-cell imaging studies using the genetically-encoded fluorescence resonance energy transfer-based reporter for PKC activity, C kinase activity reporter 2 (CKAR2), revealed that the pseudosubstrate and C1A domain mutations impaired autoinhibition to increase basal signaling. This impaired autoinhibition resulted in decreased stability of the protein, consistent with the well-characterized behavior of Ca2+-regulated PKC isozymes wherein mutations that impair autoinhibition are paradoxically loss-of-function because the mutant protein is degraded. In marked contrast, the C-terminal tail mutation resulted in enhanced autoinhibition and enhanced stability. Thus, the examined mutations were loss-of-function by different mechanisms: mutations that impaired autoinhibition promoted the degradation of PKC, and those that enhanced autoinhibition stabilized an inactive PKC. Supporting a general loss-of-function of PKCθ in cancer, bioinformatics analysis revealed that protein levels of PKCθ are reduced in diverse cancers, including lung, renal, head and neck, and pancreatic. Our results reveal that PKCθ function is lost in cancer.
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Affiliation(s)
- Stefanie J Hodapp
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Nathan Gravel
- Department of Biochemistry and Molecular Biology and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, U.S.A
| | - Natarajan Kannan
- Department of Biochemistry and Molecular Biology and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, U.S.A
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, U.S.A
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2
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Zhao X, Chen Y, Tan M, Zhao L, Zhai Y, Sun Y, Gong Y, Feng X, Du J, Fan Y. Extracellular Matrix Stiffness Regulates DNA Methylation by PKCα-Dependent Nuclear Transport of DNMT3L. Adv Healthc Mater 2021; 10:e2100821. [PMID: 34174172 DOI: 10.1002/adhm.202100821] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/31/2021] [Indexed: 01/02/2023]
Abstract
Extracellular matrix (ECM) stiffness has profound effects on the regulation of cell functions. DNA methylation is an important epigenetic modification governing gene expression. However, the effects of ECM stiffness on DNA methylation remain elusive. Here, it is reported that DNA methylation is sensitive to ECM stiffness, with a global hypermethylation under stiff ECM condition in mouse embryonic stem cells (mESCs) and embryonic fibroblasts compared with soft ECM. Stiff ECM enhances DNA methylation of both promoters and gene bodies, especially the 5' promoter regions of pluripotent genes. The enhanced DNA methylation is functionally required for the loss of pluripotent gene expression in mESCs grown on stiff ECM. Further experiments reveal that the nuclear transport of DNA methyltransferase 3-like (DNMT3L) is promoted by stiff ECM in a protein kinase C α (PKCα)-dependent manner and DNMT3L can be binding to Nanog promoter regions during cell-ECM interactions. These findings unveil DNA methylation as a novel target for the mechanical sensing mechanism of ECM stiffness, which provides a conserved mechanism for gene expression regulation during cell-ECM interactions.
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Affiliation(s)
- Xin‐Bin Zhao
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing 100083 China
| | - Yun‐Ping Chen
- Institute of Biomechanics and Medical Engineering Department of Engineering Mechanics Tsinghua University Beijing 100084 China
| | - Min Tan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing 100083 China
| | - Lan Zhao
- Institute of Biomechanics and Medical Engineering Department of Engineering Mechanics Tsinghua University Beijing 100084 China
| | - Yuan‐Yuan Zhai
- School of Materials Science and Engineering Beijing Institute of Fashion Technology Beijing 100029 China
| | - Yan‐Ling Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing 100083 China
| | - Yan Gong
- School of Materials Science and Engineering Beijing Institute of Fashion Technology Beijing 100029 China
| | - Xi‐Qiao Feng
- Institute of Biomechanics and Medical Engineering Department of Engineering Mechanics Tsinghua University Beijing 100084 China
| | - Jing Du
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing 100083 China
| | - Yu‐Bo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing 100083 China
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Wang H, Liu Y, Wang D, Xu Y, Dong R, Yang Y, Lv Q, Chen X, Zhang Z. The Upstream Pathway of mTOR-Mediated Autophagy in Liver Diseases. Cells 2019; 8:E1597. [PMID: 31835352 PMCID: PMC6953127 DOI: 10.3390/cells8121597] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/29/2019] [Accepted: 12/03/2019] [Indexed: 12/11/2022] Open
Abstract
Autophagy, originally found in liver experiments, is a cellular process that degrades damaged organelle or protein aggregation. This process frees cells from various stress states is a cell survival mechanism under stress stimulation. It is now known that dysregulation of autophagy can cause many liver diseases. Therefore, how to properly regulate autophagy is the key to the treatment of liver injury. mechanistic target of rapamycin (mTOR)is the core hub regulating autophagy, which is subject to different upstream signaling pathways to regulate autophagy. This review summarizes three upstream pathways of mTOR: the phosphoinositide 3-kinase (PI3K)/protein kinase (AKT) signaling pathway, the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, and the rat sarcoma (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-extracellular activated protein kinase kinase (MEK)/ extracellular-signal-regulated kinase (ERK) signaling pathway, specifically explored their role in liver fibrosis, hepatitis B, non-alcoholic fatty liver, liver cancer, hepatic ischemia reperfusion and other liver diseases through the regulation of mTOR-mediated autophagy. Moreover, we also analyzed the crosstalk between these three pathways, aiming to find new targets for the treatment of human liver disease based on autophagy.
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Affiliation(s)
- Haojie Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Yumei Liu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Dongmei Wang
- College of Medical, Henan University of Science and Technology, Luoyang 471000, China;
| | - Yaolu Xu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Ruiqi Dong
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Yuxiang Yang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Qiongxia Lv
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Xiaoguang Chen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
| | - Ziqiang Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, China; (H.W.); (Y.X.); (R.D.); (Y.Y.); (Q.L.); (X.C.)
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Raymundo BR, Oh I, Kim M, Kim C. Transgelin Depletion is Critical for the TGFβ1‐mediated Initiation of PLCγ1‐Cofilin‐driven Morphological and Migratory Changes in MDA‐MB‐231 Cells. B KOREAN CHEM SOC 2019. [DOI: 10.1002/bkcs.11900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Bernardo R. Raymundo
- Department of Biotechnology, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
| | - In‐Rok Oh
- Department of Biotechnology, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
| | - MiJung Kim
- Department of Biotechnology, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
- Division of Life Sciences, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
| | - Chan‐Wha Kim
- Department of Biotechnology, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
- Division of Life Sciences, College of Life Sciences and BiotechnologyKorea University Seoul 136‐701 South Korea
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Kim JM, Lee K, Jeong D. Selective regulation of osteoclast adhesion and spreading by PLCγ/PKCα-PKCδ/RhoA-Rac1 signaling. BMB Rep 2018; 51:230-235. [PMID: 29301608 PMCID: PMC5988577 DOI: 10.5483/bmbrep.2018.51.5.198] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Indexed: 01/16/2023] Open
Abstract
Bone resorption by multinucleated osteoclasts is a multistep process involving adhesion to the bone matrix, migration to resorption sites, and formation of sealing zones and ruffled borders. Macrophage colony-stimulating factor (M-CSF) and osteopontin (OPN) have been shown to be involved in the bone resorption process by respective activation of integrin αvβ3 via “inside-out” and “outside-in” signaling. In this study, we investigated the link between signal modulators known to M-CSF- and OPN-induced osteoclast adhesion and spreading. M-CSF- and OPN-induced osteoclast adhesion was achieved via activation of stepwise signals, including integrin αvβ3, PLCγ, PKCδ, and Rac1. Osteoclast spreading induced by M-CSF and OPN was shown to be controlled via sequential activation, consistent with the osteoclast adhesion processes. In contrast to osteoclast adhesion, osteoclast spreading induced by M-CSF and OPN was blocked via activation of PLCγ/PKCα/RhoA signaling. The combined results indicate that osteoclast adhesion and spreading are selectively regulated via PLCγ/PKCα-PKCδ/RhoA-Rac1 signaling.
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Affiliation(s)
- Jin-Man Kim
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu 42415; Asan Medical Center, Asan Institute for Life Sciences, Seoul 26493, Korea
| | - Kyunghee Lee
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu 42415, Korea
| | - Daewon Jeong
- Department of Microbiology, Laboratory of Bone Metabolism and Control, Yeungnam University College of Medicine, Daegu 42415, Korea
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6
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A Boolean network of the crosstalk between IGF and Wnt signaling in aging satellite cells. PLoS One 2018; 13:e0195126. [PMID: 29596489 PMCID: PMC5875862 DOI: 10.1371/journal.pone.0195126] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/16/2018] [Indexed: 12/29/2022] Open
Abstract
Aging is a complex biological process, which determines the life span of an organism. Insulin-like growth factor (IGF) and Wnt signaling pathways govern the process of aging. Both pathways share common downstream targets that allow competitive crosstalk between these branches. Of note, a shift from IGF to Wnt signaling has been observed during aging of satellite cells. Biological regulatory networks necessary to recreate aging have not yet been discovered. Here, we established a mathematical in silico model that robustly recapitulates the crosstalk between IGF and Wnt signaling. Strikingly, it predicts critical nodes following a shift from IGF to Wnt signaling. These findings indicate that this shift might cause age-related diseases.
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7
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Cardiomyocytes Sense Matrix Rigidity through a Combination of Muscle and Non-muscle Myosin Contractions. Dev Cell 2018; 44:326-336.e3. [PMID: 29396114 PMCID: PMC5807060 DOI: 10.1016/j.devcel.2017.12.024] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 11/09/2017] [Accepted: 12/22/2017] [Indexed: 12/31/2022]
Abstract
Mechanical properties are cues for many biological processes in health or disease. In the heart, changes to the extracellular matrix composition and cross-linking result in stiffening of the cellular microenvironment during development. Moreover, myocardial infarction and cardiomyopathies lead to fibrosis and a stiffer environment, affecting cardiomyocyte behavior. Here, we identify that single cardiomyocyte adhesions sense simultaneous (fast oscillating) cardiac and (slow) non-muscle myosin contractions. Together, these lead to oscillating tension on the mechanosensitive adaptor protein talin on substrates with a stiffness of healthy adult heart tissue, compared with no tension on embryonic heart stiffness and continuous stretching on fibrotic stiffness. Moreover, we show that activation of PKC leads to the induction of cardiomyocyte hypertrophy in a stiffness-dependent way, through activation of non-muscle myosin. Finally, PKC and non-muscle myosin are upregulated at the costameres in heart disease, indicating aberrant mechanosensing as a contributing factor to long-term remodeling and heart failure. Talin in cardiomyocytes is unstretched, cyclically stretched, or continuously stretched Talin stretching depends on stiffness, myofibrillar tension, and non-myofibrillar tension Non-myofibrillar contractility requires PKC, Src, FHOD1, and non-muscle myosin PKC and non-muscle myosin activity are enhanced in cardiac disease
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8
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Zuidscherwoude M, Dunlock VME, van den Bogaart G, van Deventer SJ, van der Schaaf A, van Oostrum J, Goedhart J, In ‘t Hout J, Hämmerling GJ, Tanaka S, Nadler A, Schultz C, Wright MD, Adjobo-Hermans MJW, van Spriel AB. Tetraspanin microdomains control localized protein kinase C signaling in B cells. Sci Signal 2017; 10:10/478/eaag2755. [DOI: 10.1126/scisignal.aag2755] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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9
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Zemljič Jokhadar Š, Majhenc J, Svetina S, Batista U. Positioning of integrin β1, caveolin-1 and focal adhesion kinase on the adhered membrane of spreading cells. Cell Biol Int 2013; 37:1276-84. [DOI: 10.1002/cbin.10155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 07/08/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Špela Zemljič Jokhadar
- Institute of Biophysics; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
| | - Janja Majhenc
- Institute of Biophysics; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
| | - Saša Svetina
- Institute of Biophysics; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
- Jožef Stefan Institute; Ljubljana Slovenia
| | - Urška Batista
- Institute of Biophysics; Faculty of Medicine; University of Ljubljana; Ljubljana Slovenia
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The potential of laminin-2-biomimetic short peptide to promote cell adhesion, spreading and migration by inducing membrane recruitment and phosphorylation of PKCδ. Biomaterials 2012; 33:3967-79. [DOI: 10.1016/j.biomaterials.2012.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/02/2012] [Indexed: 11/18/2022]
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11
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Oroxylin A inhibits matrix metalloproteinase-2/9 expression and activation by up-regulating tissue inhibitor of metalloproteinase-2 and suppressing the ERK1/2 signaling pathway. Toxicol Lett 2012; 209:211-20. [DOI: 10.1016/j.toxlet.2011.12.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 11/17/2022]
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12
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Protein kinase Cdelta-mediated phosphorylation of phospholipase D controls integrin-mediated cell spreading. Mol Cell Biol 2010; 30:5086-98. [PMID: 20733000 DOI: 10.1128/mcb.00443-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Integrin signaling plays critical roles in cell adhesion, spreading, and migration, and it is generally accepted that to regulate these integrin functions accurately, localized actin remodeling is required. However, the molecular mechanisms that control the targeting of actin regulation molecules to the proper sites are unknown. We previously demonstrated that integrin-mediated cell spreading and migration on fibronectin are dependent on the localized activation of phospholipase D (PLD). However, the mechanism underlying PLD activation by integrin is largely unknown. Here we demonstrate that protein kinase Cδ (PKCδ) is required for integrin-mediated PLD signaling. After integrin stimulation, PKCδ is activated and translocated to the edges of lamellipodia, where it colocalizes with PLD2. The abrogation of PKCδ activity inhibited integrin-induced PLD activation and cell spreading. Finally, we show that Thr566 of PLD2 is directly phosphorylated by PKCδ and that PLD2 mutation in this region prevents PLD2 activation, PLD2 translocation to the edge of lamellipodia, Rac translocation, and cell spreading after integrin activation. Together, these results suggest that PKCδ is a primary regulator of integrin-mediated PLD activation via the direct phosphorylation of PLD, which is essential for directing integrin-induced cell spreading.
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13
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Chen CL, Chen HC. Functional suppression of E-cadherin by protein kinase Cdelta. J Cell Sci 2009; 122:513-23. [PMID: 19174468 DOI: 10.1242/jcs.035469] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Protein kinase C (PKC) delta, a member of the novel PKC subfamily, has been shown to have an important role in cell proliferation, differentiation, apoptosis and cell motility. In this study, we investigated the effect of green fluorescent protein (GFP)-PKCdelta and GFP-PKCalpha on cell-cell junctions of Madin-Darby canine kidney (MDCK) cells and found that only GFP-PKCdelta suppressed the homophilic interactions between the ectodomains of E-cadherins, accompanied by a weaker cell-cell adhesion. The kinase-deficient mutant of GFP-PKCdelta retained its localization at cell-cell junctions but failed to suppress the function of E-cadherin. In addition, we demonstrated that the hinge region (residues 280-347) that links the regulatory domain and the catalytic domain of PKCdelta is essential for both its kinase activity and the targeting of cell-cell junctions. A PKCdelta mutant with the deletion of amino acids 280-323 within the hinge region, which is catalytically active but defective in the targeting of cell-cell junctions, failed to suppress the function of E-cadherin. Moreover, expression of GFP-PKCdelta in MDCK cells expedited the detachment of cells from their neighbors and facilitated cell scatter induced by hepatocyte growth factor. By contrast, the GFP-PKCdelta mutants including the kinase-deficient mutant and the truncated mutant lacking residues 280-323 suppressed hepatocyte-growth-factor-induced cell scattering. Finally, siRNA-mediated knockdown of endogenous PKCdelta in MDCK cells was found to delay the onset of cell-cell detachment and cell scattering induced by hepatocyte growth factor. Taken together, our results demonstrate that the catalytic activity of PKCdelta and its localization to cell-cell junctions are necessary for PKCdelta to suppress the function of E-cadherin, which thereby facilitates scattering of epithelial cells in response to extracellular cues.
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Affiliation(s)
- Chien-Lin Chen
- Department of Life Science and Graduate Institute of Biomedical Sciences, National Chung Hsing University, Taichung 40227, Taiwan
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Eisinger DA, Ammer H. Delta-opioid receptors activate ERK/MAP kinase via integrin-stimulated receptor tyrosine kinases. Cell Signal 2008; 20:2324-31. [PMID: 18804531 DOI: 10.1016/j.cellsig.2008.09.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/01/2008] [Accepted: 09/02/2008] [Indexed: 11/18/2022]
Abstract
Integrin-mediated cell adherence to extracellular matrix proteins results in stimulation of ERK1/2 activity, a mechanism involving focal adhesion tyrosine kinases (pp125FAK, Pyk-2) and epidermal growth factor receptors (EGFRs). G protein-coupled receptors (GPCRs) may also mediate ERK1/2 activation in an integrin-dependent manner, the underlying signaling mechanism of which still remains unclear. Here we demonstrate that the delta-opioid receptor (DOR), a typical GPCR, stimulates ERK1/2 activity in HEK293 cells via integrin-mediated transactivation of EGFR function. Inhibition of integrin signaling by RGDT peptides, cytochalasin, and by keeping the cells in suspension culture both blocked [D-Ala(2), D-Leu(5)]enkephalin (DADLE)- and etorphine-stimulated ERK1/2 activity. Integrin-dependent ERK1/2 activation does not involve FAK/Pyk-2, because over-expression of the FAK/Pyk-2 inhibitor SOCS-3 failed to attenuate DOR signaling. Exposure of the cells to the EGFR inhibitors AG1478 and BPIQ-I blocked DOR-mediated ERK1/2 activation. Because RGDT peptides also prevented DOR-mediated EGFR activation, the present findings indicate that in HEK293 cells DOR-stimulated ERK1/2 activity is mediated by integrin-stimulated EGFRs. Further studies with the phospholipase C (PLC) inhibitors U73122 and ET-18-OCH(3) revealed that opioid-stimulated integrin activation is sensitive to PLC. In contrast, integrin-mediated transactivation of EGFR function appears to be dependent on PKC-delta, as indicated by studies with rottlerin and siRNA knock-down. A similar ERK1/2 signaling pathway was observed for NG108-15 cells, a neuronal cell line endogenously expressing the DOR. In these cells, the nerve growth factor TrkA receptor replaces the EGFR in connecting DOR-activated integrins to the Ras/Raf/ERK1/2 pathway. Together, these data describe an alternative ERK1/2 signaling pathway in which the DOR transactivates the growth factor receptor associated mitogen-activated protein kinase cascade in an integrin-dependent manner.
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Affiliation(s)
- Daniela A Eisinger
- Institute of Pharmacology, Toxicology and Pharmacy, University of Munich, Königinstrasse 16, D-80539 München, Germany.
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Oh MA, Kang ES, Lee SA, Lee EO, Kim YB, Kim SH, Lee JW. PKCdelta and cofilin activation affects peripheral actin reorganization and cell-cell contact in cells expressing integrin alpha5 but not its tailless mutant. J Cell Sci 2007; 120:2717-30. [PMID: 17646675 DOI: 10.1242/jcs.003566] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Integrin-mediated cell adhesion transduces signaling activities for actin reorganization, which is crucially involved in cellular function and architectural integrity. In this study, we explored the possibility of whether cell-cell contacts might be regulated via integrin-alpha5beta1-mediated actin reorganization. Ectopic expression of integrin alpha5 in integrin-alpha5-null intestinal epithelial cells resulted in facilitated retraction, cell-cell contact loss, and wound healing depending on Src and PI3K (phosphoinositide 3-kinase) activities by a reagent that affects actin organization. However, cytoplasmic tailless integrin alpha5 (hereafter referred to as alpha5/1) expression caused no such effects but rather sustained peripheral actin fibers, regardless of Src and PI3K signaling activities. Furthermore, integrin alpha5 engagement with fibronectin phosphorylated Ser643 of PKCdelta, upstream of FAK and Src and at a transmodulatory loop with PI3K/Akt. Pharmacological PKCdelta inactivation, dominant-negative PKCdelta adenovirus or inactive cofilin phosphatase (SSH1L mutant) retrovirus infection of alpha5-expressing cells sustained peripheral actin organization and blocked the actin reorganizing-mediated loss of cell-cell contacts. Meanwhile, wild-type PKCdelta expression sensitized alpha5/1-expressing cells to the actin disruptor to induce cell scattering. Altogether, these observations indicate that integrin alpha5, but not alpha5/1, mediates PKCdelta phosphorylation and cofilin dephosphorylation, which in turn modulate peripheral actin organization presumably leading to an efficient regulation of cell-cell contact and migration.
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Affiliation(s)
- Min-A Oh
- Cancer Research Institute, College of Medicine, Seoul National University, 28, Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea
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16
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Kim SD, Yang SI, Kim HC, Shin CY, Ko KH. Inhibition of GSK-3beta mediates expression of MMP-9 through ERK1/2 activation and translocation of NF-kappaB in rat primary astrocyte. Brain Res 2007; 1186:12-20. [PMID: 17996850 DOI: 10.1016/j.brainres.2007.10.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 09/30/2007] [Accepted: 10/05/2007] [Indexed: 10/22/2022]
Abstract
Glycogen synthase kinase (GSK)-3beta and extracellular signal-regulated kinase (ERK) regulate several cellular signaling pathways in common, including embryonic development, cell differentiation and apoptosis. In this study, we investigated whether GSK-3beta inhibition is involved in ERK activation, which affects the activation of NF-kappaB and induction of MMP-9 in cultured rat primary astrocytes. Here, we found that GSK-3beta inhibition using GSK-3beta inhibitor TDZD-8 increased the phosphorylation of GSK-3beta at Ser9 site as well as the phosphorylation of ERK1/2 and Akt at Ser473 site. In this condition, GSK-3beta inhibition increased MMP-9 but not MMP-2 activity in a concentration-dependent manner. In RT-PCR analysis, MMP-9 mRNA level was increased by GSK-3beta inhibition in a concentration-dependent manner. MMP-9 promoter reporter activity was similarly increased by GSK-3beta inhibition. Pretreatment of U-0126 (MEK1/2 inhibitor) completely abolished the GSK-3beta inhibition-induced phosphorylation of ERK1/2. U-0126 prevented GSK-3beta inhibition-mediated induction of MMP-9 reporter activity as well as the MMP-9 gene expression. The transcriptional activity of NF-kappaB was significantly increased by GSK-3beta inhibition, which was determined by nuclear translocation of NF-kappaB. Inhibition of ERK1/2 activity by U-0126 also completely blocked the nuclear translocation of NF-kappaB. Transfection of dominant negative plasmid (S9A) of GSK-3beta significantly decreased phosphorylation of ERK, MMP-9 expression and nuclear translocation of NF-kappaB by GSK-3beta inhibition as compared to wild type GSK-3beta. These data suggest that GSK-3beta inhibition mediates ERK1/2 activation followed by NF-kappaB activation, which directly regulates the induction of MMP-9 in rat primary astrocytes.
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Affiliation(s)
- Sun Don Kim
- Laboratory of Pharmacology, College of Pharmacy, Seoul National University, Seoul [151-742], Republic of Korea
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Wheeler DL, Li Y, Verma AK. Protein Kinase C Epsilon Signals Ultraviolet Light-induced Cutaneous Damage and Development of Squamous Cell Carcinoma Possibly Through Induction of Specific Cytokines in a Paracrine Mechanism¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb01516.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Abstract
Inflammation caused by Borrelia burgdorferi infection occurs as a result of induction of pro-inflammatory cytokines from activation of multiple signalling pathways. It has previously been shown that mitogen-activated protein kinase (MAPK) and Janus kinase/signal transducer and activator of transcription signalling pathways are activated by B. burgdorferi in cultured human chondrocytes. Protein kinase C (PKC) signalling pathways are potential candidates that may control these downstream signalling pathways. Here we show that B. burgdorferi infection leads to phosphorylation and activation of novel PKC isoforms (PKC delta, epsilon, eta and theta) in a time-dependent manner. A specific inhibitor of novel PKC isoforms blocked the induction of pro-inflammatory molecules in response to B. burgdorferi infection as did transient transfection of novel PKC dominant-negative plasmids into chondrocytes. B. burgdorferi-induced p38 MAPK phosphorylation was also significantly inhibited by an inhibitor of novel PKC isoforms, suggesting that PKC activation occurs upstream of p38 activation. In vivo, administration of an inhibitor of classical and novel PKC isoforms to C3H/HeN mice infected with B. burgdorferi resulted in significantly reduced ankle inflammation and swelling. In conclusion, these data suggest that novel PKC isoforms are specifically activated by B. burgdorferi infection and this can contribute to the regulation of inflammation in vitro and in vivo.
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Affiliation(s)
- Ok S. Shin
- Tufts New England Medical Center, Tufts University School of Medicine, Tupper Research Institute, Division of Geographic Medicine and Infectious Diseases, Boston, Massachusetts 02111, USA
| | - Aruna K. Behera
- Tufts New England Medical Center, Tufts University School of Medicine, Tupper Research Institute, Division of Geographic Medicine and Infectious Diseases, Boston, Massachusetts 02111, USA
| | - Roderick T. Bronson
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Linden T. Hu
- Tufts New England Medical Center, Tufts University School of Medicine, Tupper Research Institute, Division of Geographic Medicine and Infectious Diseases, Boston, Massachusetts 02111, USA
- Corresponding author: Linden Hu, Tufts-New England Medical Center, 750, Washington St., Boston, MA 02111, phone: (617) 636-8498, fax: (617) 636-3216,
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19
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Potthoff S, Entschladen F, Niggemann B, Zaenker KS, Lang K. N-cadherin engagement provides a dominant stop signal for the migration of MDA-MB-468 breast carcinoma cells. Breast Cancer Res Treat 2006; 105:287-95. [PMID: 17171299 DOI: 10.1007/s10549-006-9458-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 11/13/2006] [Indexed: 10/24/2022]
Abstract
The development of a primary tumor as such is not the main cause of death, but is rather the spreading of metastases, which causes over 90% of deaths in cancer patients. This largely depends on the ability of tumor cells to migrate away from the tumor and relocate at other areas of the body. Cell migration is known to be regulated by various extracellular signal substances such as neurotransmitters. However, before single tumor cells can start to invade into distant tissue, they have to dissociate from the primary tumor. This requires the disruption of cell-cell contacts, which are provided by a plethora of adhesion molecules like the family of cadherins. Using our well, established three-dimensional collagen-based cell migration assay, we show that engagement of N-cadherin results in a significant decrease of the spontaneous and the norepinephrine-induced migration of MDA-MB-468 breast carcinoma cells, which was due to an increase in the average break length. Moreover, this N-cadherin driven influence on the migratory activity is intracellularly integrated via multiple signaling pathways. Our results show that the impact of N-cadherin on the locomotion of MDA cells involves the activation of the adenylyl cyclase and the phosphatidylinositol-3-kinase (PI3K), but is independent of the protein kinase C (PKC) alpha. In summary, we provide evidence that the engagement of N-cadherin provides a stop signal for breast carcinoma cell migration, and accordingly the use of anti-N-cadherin antibodies or soluble ligands might be a tool to inhibit metastasis formation in E-cadherin negative but N-cadherin positive tumors.
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Affiliation(s)
- S Potthoff
- Institute for Immunology, Witten/Herdecke University, Stockumer Str. 10, Witten , 58448, Germany
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20
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Xu J, Xie Z, Reece R, Pimental D, Zou MH. Uncoupling of Endothelial Nitric Oxidase Synthase by Hypochlorous Acid. Arterioscler Thromb Vasc Biol 2006; 26:2688-95. [PMID: 17023679 DOI: 10.1161/01.atv.0000249394.94588.82] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The aim of the present study is to determine whether hypochlorous acid (HOCl), the major oxidant of leukocyte-derived myeloperoxidase (MPO), oxidizes the zinc-thiolate center of endothelial nitric oxide synthase (eNOS) and uncouples the enzyme. METHODS AND RESULTS Exposure of purified recombinant eNOS to HOCl (> or = 100 micromol/L) released zinc and disrupted the enzyme-active eNOS dimers. In parallel with increased detections of both O2*- and ONOO-, clinically relevant concentrations of HOCl disrupted eNOS dimers in cultured human umbilical vein endothelial cells (HUVEC) at concentration 10- to 100-fold lower than those required for recombinant eNOS. In HUVEC, HOCl increased the translocation of both p67(phox) and p47(phox) of NAD(P)H oxidase and the phosphorylation of atypical protein kinase C-zeta. Further, genetic or pharmacological inhibition of either NAD(P)H oxidase-derived O2*- or PKC-zeta or NOS abolished the effects of HOCl on eNOS dimers. Consistently, HOCl increased both O2*- and ONOO- and eNOS dimer oxidation in isolated mouse aortas from C57BL/6 but less in those of gp91(phox) knock-out mice. Finally, in human carotid atherosclerotic arteries, eNOS predominantly existed as monomers in parallel with increased staining of both MPO and 3-nitrotyrosine. CONCLUSIONS We conclude that HOCl uncouples eNOS by ONOO- generated from PKC-zeta-dependent NAD(P)H oxidase.
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Affiliation(s)
- Jian Xu
- Section of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, 941 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
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21
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Osmanagic-Myers S, Gregor M, Walko G, Burgstaller G, Reipert S, Wiche G. Plectin-controlled keratin cytoarchitecture affects MAP kinases involved in cellular stress response and migration. ACTA ACUST UNITED AC 2006; 174:557-68. [PMID: 16908671 PMCID: PMC2064261 DOI: 10.1083/jcb.200605172] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plectin is a major intermediate filament (IF)-based cytolinker protein that stabilizes cells and tissues mechanically, regulates actin filament dynamics, and serves as a scaffolding platform for signaling molecules. In this study, we show that plectin deficiency is a cause of aberrant keratin cytoskeleton organization caused by a lack of orthogonal IF cross-linking. Keratin networks in plectin-deficient cells were more susceptible to osmotic shock-induced retraction from peripheral areas, and their okadaic acid-induced disruption (paralleled by stress-activated MAP kinase p38 activation) proceeded faster. Basal activities of the MAP kinase Erk1/2 and of the membrane-associated upstream protein kinases c-Src and PKCdelta were significantly elevated, and increased migration rates, as assessed by in vitro wound-closure assays and time-lapse microscopy, were observed. Forced expression of RACK1, which is the plectin-binding receptor protein for activated PKCdelta, in wild-type keratinocytes elevated their migration potential close to that of plectin-null cells. These data establish a link between cytolinker-controlled cytoarchitecture/scaffolding functions of keratin IFs and specific MAP kinase cascades mediating distinct cellular responses.
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Affiliation(s)
- Selma Osmanagic-Myers
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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22
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Plows LD, Cook RT, Davies AJ, Walker AJ. Integrin engagement modulates the phosphorylation of focal adhesion kinase, phagocytosis, and cell spreading in molluscan defence cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:779-86. [PMID: 16766054 DOI: 10.1016/j.bbamcr.2006.04.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 04/07/2006] [Accepted: 04/07/2006] [Indexed: 12/21/2022]
Abstract
Integrins play a key role in cellular immune responses in a variety of organisms; however, knowledge of integrins and their effects on cell signalling and functional responses in molluscan defence reactions is poor. Using integrin-mediated cell adhesion kits, alphaVbeta3 and beta1 integrin-like subunits were identified on the surface of Lymnaea stagnalis haemocytes. Haemocyte binding via these integrins was found to be dependent on Ca2+/Mg2+. Western blotting with an anti-phospho (anti-active) focal adhesion kinase (FAK) antibody revealed a 120-125 kDa FAK-like protein in these cells; this protein was transiently phosphorylated upon haemocyte adhesion over 90 min, with maximal phosphorylation occurring after 30 min binding. Also, integrin engagement with the tetrapeptide Arg-Gly-Asp-Ser (RGDS) resulted in a rapid increase in phosphorylation of the FAK-like protein; however, RGDS did not affect the phosphorylation of extracellular signal-regulated kinase. Treatment of haemocytes with RGDS (2 mM) inhibited phagocytosis of E. coli bioparticles by 88%. Moreover, at this concentration, RGDS reduced cell spreading by 61%; stress fiber formation was also impaired. Taken together, these results demonstrate a role for integrins in L. stagnalis haemocyte adhesion and defence reactions and, for the first time, link integrin engagement to FAK activation in molluscs.
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Affiliation(s)
- Louise D Plows
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey, KT1 2EE, UK
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23
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Hawes JJ, Narasimhaiah R, Picciotto MR. Galanin and galanin-like peptide modulate neurite outgrowth via protein kinase C-mediated activation of extracellular signal-related kinase. Eur J Neurosci 2006; 23:2937-46. [PMID: 16819983 DOI: 10.1111/j.1460-9568.2006.04828.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The neuropeptide galanin is widely distributed in the central nervous system and plays a role in a number of processes in the adult brain. Galanin also has neurotrophic effects in the developing nervous system and after nerve injury. The current study investigated the mechanism by which galanin promotes neurite outgrowth in the neuronal cell line PC12 and in neurospheres derived from adult hippocampal progenitor cells. We demonstrated that galanin can induce extracellular signal-related kinase (ERK) phosphorylation transiently in a concentration-dependent manner in neurons. Galanin-like peptide, which is thought to signal primarily through the GalR2 receptor subtype, induced ERK phosphorylation with similar kinetics to galanin. In functional studies, the ability of galanin and galanin-like peptide to induce neurite outgrowth was dependent on activation of both protein kinase C and ERK. This study identified a novel physiological role for galanin-induced ERK phosphorylation and identified ERK and protein kinase C as important signaling components in the galanin-mediated modulation of neurite outgrowth.
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Affiliation(s)
- Jessica J Hawes
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd floor research, New Haven, CT 06508, USA
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24
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Wang Q, Zhou Y, Wang X, Evers BM. Glycogen synthase kinase-3 is a negative regulator of extracellular signal-regulated kinase. Oncogene 2006; 25:43-50. [PMID: 16278684 PMCID: PMC1413679 DOI: 10.1038/sj.onc.1209004] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Glycogen-synthase kinase-3 (GSK-3) and extracellular signal-regulated kinase (ERK) are critical downstream signaling proteins for the PI3-kinase/Akt and Ras/Raf/MEK-1 pathway, respectively, and regulate diverse cellular processes including embryonic development, cell differentiation and apoptosis. Here, we show that inhibition of GSK-3 using GSK-3 inhibitors or RNA interference (RNAi) significantly induced the phosphorylation of ERK1/2 in human colon cancer cell lines HT29 and Caco-2. Pretreatment with the PKCdelta-selective inhibitor rottlerin or transfection with PKCdelta siRNA attenuated the phosphorylation of ERK1/2 induced by the GSK-3 inhibitor SB-216763 and, furthermore, treatment with SB-216763 or transfection with GSK-3alpha and GSK-3beta siRNA increased PKCdelta activity, thus identifying a role for PKCdelta in the induction of ERK1/2 phosphorylation by GSK-3 inhibition. Treatment with SB-216763 increased expression of cyclooxygenase-2 (COX-2) and IL-8, which are downstream targets of ERK1/2 activation; this induction was abolished by MEK/ERK inhibition, suggesting GSK-3 inhibition induced COX-2 and IL-8 through ERK1/2 activation. The transcriptional induction of COX-2 and IL-8 by GSK-3 inhibition was further demonstrated by the increased COX-2 and IL-8 promoter activity after SB-216763 treatment or transfection with GSK-3alpha or GSK-3beta siRNA. Importantly, our findings identify GSK-3, acting through PKCdelta, as a negative regulator of ERK1/2, thus revealing a novel crosstalk mechanism between these critical signaling pathways.
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Affiliation(s)
| | | | | | - B Mark Evers
- Department of Surgery and
- The Sealy Center for Cancer Cell Biology The University of Texas Medical Branch Galveston, Texas
- Correspondence: B. Mark Evers, M.D., Department of Surgery, The University of Texas Medical Branch 301 University Boulevard, Galveston, TX 77555-0536, Telephone: (409) 772-5254, FAX: (409) 747-4819 e-mail:
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25
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Zheng M, McKeown-Longo PJ. Cell adhesion regulates Ser/Thr phosphorylation and proteasomal degradation of HEF1. J Cell Sci 2005; 119:96-103. [PMID: 16352661 DOI: 10.1242/jcs.02712] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human enhancer of filamentation 1 (HEF1), a multifunctional docking protein of the Cas family, participates in integrin and growth factor signaling pathways that regulate global cellular processes including growth, motility and apoptosis. HEF1 consists of two isoforms, p105 and p115, the larger molecular weight form resulting from Ser/Thr phosphorylation of p105HEF1. The molecular mechanisms that regulate the interconversion of the two HEF1 species as well as the function of HEF1 Ser/Thr phosphorylation are unknown. Our study reveals that cell adhesion and detachment regulate the interconversion of the two HEF1 isoforms. Experiments using various inhibitors of cytoskeletal organization indicated that disruption of actin microfilaments but not intermediate filaments or microtubules resulted in a complete conversion of p115HEF1 to p105HEF1. The conversion of p115HEF1 to p105HEF1 was prevented by inhibition of protein phosphatase 2A (PP2A), suggesting that cytoskeletal regulation of PP2A activity controlled the dephosphorylation of p115HEF1. Degradation of endogenous HEF1 was dependent on proteasomes with the p115 species of HEF1 being preferentially targeted for turnover. Dephosphorylation of HEF1 by suspending cells or disrupting actin filaments protected HEF1 from degradation. These results suggest that the adhesion-dependent actin organization regulates proteasomal turnover of HEF1 through the activity of PP2A.
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Affiliation(s)
- Mingzhe Zheng
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, NY 12208, USA
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26
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Wang J, Milner R. Fibronectin promotes brain capillary endothelial cell survival and proliferation through alpha5beta1 and alphavbeta3 integrins via MAP kinase signalling. J Neurochem 2005; 96:148-59. [PMID: 16269008 DOI: 10.1111/j.1471-4159.2005.03521.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We showed previously that blood vessel maturation in the CNS is associated with a developmental switch in brain capillary endothelial cells (BCEC), from fibronectin signalling during angiogenesis to laminin signalling in the adult. To investigate the functional significance of this switch, we have examined the response of BCEC to different extracellular matrix (ECM) proteins. This showed that BCEC proliferation was significantly promoted by fibronectin (28.2 +/- 4.0%) and by vitronectin (14.8 +/- 2.1%) compared with uncoated glass (7.2 +/- 0.7%), while BCEC survival was significantly promoted by fibronectin (1130 +/- 131 cells), vitronectin (830 +/- 63 cells), collagen IV (703 +/- 77 cells) and laminin (680 +/- 34 cells) compared with the uncoated glass (367 +/- 48 cells). Biochemical studies showed that BCEC express a limited repertoire of integrins, including the beta1 integrins, alpha3beta1, alpha5beta1 and alpha6beta1, and the alphavbeta3 integrin. Function-blocking studies showed that the response to fibronectin was mediated equally by the alpha5beta1 and alphavbeta3 integrins. Analysis of signalling pathways revealed that fibronectin stimulated activation of the p44/p42 MAP kinase signalling pathway and pharmacological inhibitors of this pathway blocked BCEC proliferation on fibronectin. Taken together, these findings show that fibronectin exerts a strong angiogenic influence on endothelial cells (EC) in the CNS, and that this is mediated through the alpha5beta1 and alphavbeta3 integrins via MAP kinase signalling. In addition to a fundamental role in development, these findings may also have implications in pathological conditions of the CNS where fibronectin is re-expressed.
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Affiliation(s)
- Jan Wang
- The Department of Pathology, University of Cambridge, Cambridge, UK
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27
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Rucci N, DiGiacinto C, Orrù L, Millimaggi D, Baron R, Teti A. A novel protein kinase C α-dependent signal to ERK1/2 activated by αVβ3 integrin in osteoclasts and in Chinese hamster ovary (CHO) cells. J Cell Sci 2005; 118:3263-75. [PMID: 16014375 DOI: 10.1242/jcs.02436] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We identified a novel protein kinase C (PKC)α-dependent signal to extracellular signal-regulated kinase (ERK)1/2 in mouse osteoclasts and Chinese hamster ovary (CHO) cells, specifically activated by the αVβ3 integrin. It involves translocation (i.e. activation) of PKCα from the cytosol to the membrane and/or the Triton X-100-insoluble subcellular fractions, with recruitment into a complex with αVβ3 integrin, growth factor receptor-bound protein (Grb2), focal adhesion kinase (FAK) in CHO cells and proline-rich tyrosine kinase (PYK2) in osteoclasts. Engagement of αvβ3 integrin triggered ERK1/2 phosphorylation, but the underlying molecular mechanism was surprisingly independent of the well known Shc/Ras/Raf-1 cascade, and of phosphorylated MAP/ERK kinase (MEK)1/2, so far the only recognized direct activator of ERK1/2. In contrast, PKCα was involved in ERK1/2 activation because inhibition of its activity prevented ERK1/2 phosphorylation. The tyrosine kinase c-Src also contributed to ERK1/2 activation, however, it did not interact with PKCα in the same molecular complex. The αVβ3/PKCα complex formation was fully dependent upon the intracellular calcium concentration ([Ca2+]i), and the use of the intracellular Ca2+ chelator 1,2-bis(o-amino-phenoxy)ethane-N,N,N′,N′-tetraaceticacidtetra (acetoxymethyl) ester (BAPTA-AM) also inhibited PKCα translocation and ERK1/2 phosphorylation. Functional studies showed that αVβ3 integrin-activated PKCα was involved in cell migration and osteoclast bone resorption, but had no effect on the ability of cells to attach to LM609, suggesting a role in events downstream of αVβ3 integrin engagement.
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Affiliation(s)
- Nadia Rucci
- Department of Experimental Medicine, University of L'Aquila, via Vetoio - Coppito 2, 67100, L'Aquila, Italy
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28
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Dina OA, Hucho T, Yeh J, Malik-Hall M, Reichling DB, Levine JD. Primary afferent second messenger cascades interact with specific integrin subunits in producing inflammatory hyperalgesia. Pain 2005; 115:191-203. [PMID: 15836982 DOI: 10.1016/j.pain.2005.02.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 02/11/2005] [Accepted: 02/22/2005] [Indexed: 01/19/2023]
Abstract
We recently reported that hyperalgesia induced by the inflammatory mediator prostaglandin E(2) (PGE(2)) requires intact alpha1, alpha3 and beta1 integrin subunit function, whereas epinephrine-induced hyperalgesia depends on alpha5 and beta1. PGE(2)-induced hyperalgesia is mediated by protein kinase A (PKA), while epinephrine-induced hyperalgesia is mediated by a combination of PKA, protein kinase Cepsilon (PKCepsilon) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK). We hypothesized that inflammatory mediator-induced hyperalgesia involves specific interactions between different subsets of integrin subunits and particular second messenger species. In the present study, function-blocking anti-integrin antibodies and antisense oligodeoxynucleotides were used to elucidate these interactions in rat. Hyperalgesia produced by an activator of adenylate cyclase (forskolin) depended on alpha1, alpha3 and beta1 integrins. However, hyperalgesia induced by activation of the cascade at a point farther downstream (by cAMP analog or PKA catalytic subunit) was independent of any integrins tested. In contrast, hyperalgesia induced by a specific PKCepsilon agonist depended only on alpha5 and beta1 integrins. Hyperalgesia induced by agonism of MAPK/ERK depended on all four integrin subunits tested (alpha1, alpha3, alpha5 and beta1). Finally, disruption of lipid rafts antagonized hyperalgesia induced by PGE(2) and by forskolin, but not that induced by epinephrine. Furthermore, alpha1 integrin, but not alpha5, was present in detergent-resistant membrane fractions (which retain lipid raft components). These observations suggest that integrins play a critical role in inflammatory pain by interacting with components of second messenger cascades that mediate inflammatory hyperalgesia, and that such interaction with the PGE(2)-activated pathway may be organized by lipid rafts.
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Affiliation(s)
- Olayinka A Dina
- Department of Medicine, Division of Neuroscience and Biomedical Sciences Program, NIH Pain Center (UCSF), University of California at San Francisco, Campus Box 0440, Room C-555 521, San Francisco, CA 94143-0440, USA
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29
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Jørgensen K, Skrede M, Cruciani V, Mikalsen SO, Slipicevic A, Flørenes VA. Phorbol ester phorbol-12-myristate-13-acetate promotes anchorage-independent growth and survival of melanomas through MEK-independent activation of ERK1/2. Biochem Biophys Res Commun 2005; 329:266-74. [PMID: 15721302 DOI: 10.1016/j.bbrc.2005.01.143] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Indexed: 11/21/2022]
Abstract
The phorbol ester, phorbol-12-myristate-13-acetate (PMA), an activator of PKCs, is known to stimulate the in vitro growth of monolayer cultures of normal human melanocytes whereas it inhibits the growth of most malignant melanoma cell lines. We examined the effect of PMA on proliferation and survival of melanoma cells grown as multicellular aggregates in suspension (spheroids), and aimed to elucidate downstream targets of PKC signaling. In contrast to monolayer cultures, PMA increased cell proliferation as well as protected melanoma cells from suspension-mediated apoptosis (anoikis). Supporting the importance of PKC in anchorage-independent growth, treatment of anoikis-resistant melanoma cell lines with antisense oligonucleotides against PKC-alpha, or the PKC inhibitor Gö6976, strongly induced anoikis. PMA induced activation of ERK1/2, but this effect was not prevented by the MEK inhibitors PD98059 or by U0126. Whereas PD98059 treatment alone led to marked activation of the pro-apoptotic Bim and Bad proteins and significantly increased anoikis, these effects were clearly reversed by PMA. In conclusion, our results indicate that the protective effect of PMA on anchorage-independent survival of melanoma cells at least partly is mediated by MEK-independent activation of ERK1/2 and inactivation of downstream pro-apoptotic effector proteins.
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Affiliation(s)
- Kjersti Jørgensen
- Department of Pathology, The Norwegian Radium Hospital, HF, 0310 Oslo, Norway
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30
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Wheeler DL, Reddig PJ, Ness KJ, Leith CP, Oberley TD, Verma AK. Overexpression of protein kinase C-{epsilon} in the mouse epidermis leads to a spontaneous myeloproliferative-like disease. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 166:117-26. [PMID: 15632005 PMCID: PMC1602310 DOI: 10.1016/s0002-9440(10)62237-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Protein kinase C (PKC)-epsilon, a Ca(2+)-independent, phospholipid-dependent serine/threonine kinase, is among the PKC isoforms expressed in mouse epidermis. We reported that FVB/N transgenic mouse lines that overexpress (8- or 18-fold) PKC-epsilon protein in basal epidermal cells and cells of the hair follicle develop papilloma-independent squamous cell carcinoma (SCC) elicited by 7,12-dimethylbenz(a)anthracene initiation and 12-O-tetradecanoylphorbol-13-acetate-promotion or by repeated ultraviolet radiation exposures. The susceptibility to the development of SCC was proportional to the level of expression of the PKC-epsilon transgene. We now report that PKC-epsilon FVB/N transgenic mice (line 215) that overexpress in epidermis approximately 18-fold PKC-epsilon protein more than their wild-type littermates spontaneously develop a myeloproliferative-like disease (MPD) in 100% of PKC-epsilon transgenic mice. The MPD was characterized by an excess of neutrophils and eosinophils, resulting in invasion of almost all vital organs of the mouse by 6 months of age. On gross examination these mice present with splenomegaly, hepatomegaly, and severe lymphadenopathy. Examination of the bone marrow revealed almost complete effacement by neutrophils, eosinophils, and their precursors. Furthermore, the spleen and lymph nodes were enlarged and exhibited marked extramedullary hematopoiesis. Complete pathological analysis of the second PKC-epsilon transgenic mouse (line 224) that expresses approximately eightfold PKC-epsilon protein more than their wild-type littermates revealed no remarkable findings in any of the affected organs as seen in line 215. However, peripheral blood analyses of PKC-epsilon transgenic mice indicated significant increases of neutrophils in the circulating blood in both PKC-epsilon transgenic lines. To determine whether there was an imbalance of cytokines in PKC-epsilon transgenic mice (line 215), resulting in aberrant myelopoiesis, we analyzed 17 cytokines in the peripheral blood. This analysis indicated that interleukin-5, interleukin-6, and granulocyte-colony stimulating factor were up-regulated as a function of age. The transgene PKC-epsilon was not detected in any of the affected organs (bone marrow, liver, spleen, lung) We suggest that overexpression of PKC-epsilon in the epidermis may lead to the induction of specific cytokines that may, in a paracrine mechanism, perturb normal hematopoiesis in bone marrow resulting in a granulocytic skew toward that of neutrophils and eosinophils. The susceptibility of PKC-epsilon transgenic mice to the induction of SCC and the spontaneous development of MPD are unrelated.
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Affiliation(s)
- Deric L Wheeler
- Department of Human Oncology, Medical School, University of Wisconsin, K4/532 CSC Clinical Science Center, 600 Highland Ave., Madison, WI 53792, USA
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31
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Hasegawa Y, Fujitani M, Hata K, Tohyama M, Yamagishi S, Yamashita T. Promotion of axon regeneration by myelin-associated glycoprotein and Nogo through divergent signals downstream of Gi/G. J Neurosci 2005; 24:6826-32. [PMID: 15282288 PMCID: PMC6729720 DOI: 10.1523/jneurosci.1856-04.2004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Several myelin-derived proteins have been identified as components of the CNS myelin that prevents axonal regeneration in the adult vertebrate CNS. Activation of RhoA has been shown to be an essential part of the signaling mechanism of these proteins. Here we report an additional signal, which determines whether these proteins promote or inhibit axon outgrowth. Myelin-associated glycoprotein (MAG) and Nogo trigger the intracellular elevation of Ca2+ as well as the activation of PKC, presumably mediated by G(i)/G. Neurite outgrowth inhibition and growth cone collapse by MAG or Nogo can be converted to neurite extension and growth cone spreading by inhibiting conventional PKC, but not by inhibiting inositol 1,4,5-triphosphate (IP3). Conversely, neurite growth of immature neurons promoted by MAG is abolished by inhibiting IP3. Activation of RhoA is independent of PKC. Thus, a balance between PKC and IP3 is important for bidirectional regulation of axon regeneration by the myelin-derived proteins.
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Affiliation(s)
- Yuiko Hasegawa
- Department of Neurobiology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
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Urtreger AJ, Grossoni VC, Falbo KB, Kazanietz MG, Bal de Kier Joffé ED. Atypical protein kinase C-zeta modulates clonogenicity, motility, and secretion of proteolytic enzymes in murine mammary cells. Mol Carcinog 2005; 42:29-39. [PMID: 15546134 DOI: 10.1002/mc.20066] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this paper, we investigated whether protein kinase C-zeta (PKC zeta), a member of the atypical PKC family, induces phenotypic alterations associated with malignant transformation and tumor progression in mammary cells. The stable overexpression of PKC zeta in immortalized mammary epithelial cells (NMuMG), activates the mitogenic extracellular signal-regulated kinase (ERK) pathway, enhanced clonal cell growth and exerts profound effects on proteases secretion. The effect on proteases expression seems to be specific for urokinase-type plasminogen activator and metalloproteinase-9 (MMP-9) because no modulation in MMP-2 and MMP-3 production could be detected. In addition, our experiments demonstrated that PKC zeta overexpression markedly altered the adhesive, spreading, and migratory abilities of NMuMG cells. The overexpression of this enzyme was not sufficient to confer an anchorage-independent growth capacity. An extensive mutational analysis of PKC zeta revealed that the effects observed in NMuMG cells were strictly dependent on the kinase (catalytic) domain of the enzyme. Taken together, these results suggest that in mammary cells PKC zeta modulates several of the critical events involved in tumor development and dissemination through the activation of mitogen activated protein kinase (MAPK)/ERK pathway.
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Affiliation(s)
- Alejandro J Urtreger
- Research Area, Institute of Oncology Angel H. Roffo, University of Buenos Aires, C1417DTB Buenos Aires, Argentina
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Wheeler DL, Li Y, Verma AK. Protein Kinase C Epsilon Signals Ultraviolet Light-induced Cutaneous Damage and Development of Squamous Cell Carcinoma Possibly Through Induction of Specific Cytokines in a Paracrine Mechanism¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-08-12-ra-271.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wu C. The PINCH-ILK-parvin complexes: assembly, functions and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1692:55-62. [PMID: 15246679 DOI: 10.1016/j.bbamcr.2004.01.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Accepted: 01/23/2004] [Indexed: 01/18/2023]
Abstract
Cell-extracellular matrix (ECM) adhesion is mediated by transmembrane cell adhesion receptors (e.g., integrins) and receptor proximal cytoplasmic proteins. Over the past several years, studies using biochemical, structural, cell biological and genetic approaches have provided important evidence suggesting crucial roles of integrin-linked kinase (ILK), PINCH and CH-ILKBP/actopaxin/affixin/parvin (abbreviated as parvin herein) in ECM control of cell behavior. One general theme emerging from these studies is that the formation of ternary protein complexes consisting of ILK, PINCH and parvin is pivotal to the functions of PINCH, ILK and parvin proteins. In addition, recent studies have begun to uncover the molecular mechanisms underlying the assembly, functions and regulation of the PINCH-ILK-parvin (PIP) complexes. The PIP complexes provide crucial physical linkages between integrins and the actin cytoskeleton and transduce diverse signals from ECM to intracellular effectors. Among the challenges of future studies are to define the functions of different PIP complexes in various cellular processes, identify additional partners of the PIP complexes that regulate and/or mediate the functions of the PIP complexes, and determine the roles of the PIP complexes in the pathogenesis of human diseases involving abnormal cell-ECM adhesion and signaling.
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Affiliation(s)
- Chuanyue Wu
- Department of Pathology, University of Pittsburgh, 707B Scaife Hall, 3550 Terrace Street, PA 15261, USA.
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35
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Wheeler DL, Martin KE, Ness KJ, Li Y, Dreckschmidt NE, Wartman M, Ananthaswamy HN, Mitchell DL, Verma AK. Protein kinase C epsilon is an endogenous photosensitizer that enhances ultraviolet radiation-induced cutaneous damage and development of squamous cell carcinomas. Cancer Res 2004; 64:7756-65. [PMID: 15520180 DOI: 10.1158/0008-5472.can-04-1881] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic exposure to UV radiation (UVR), especially in the UVA (315-400 nm) and UVB (280-315 nm) spectrum of sunlight, is the major risk factor for the development of nonmelanoma skin cancer. UVR is a complete carcinogen, which both initiates and promotes carcinogenesis. We found that protein kinase C epsilon (PKCepsilon), a member of the phospholipid-dependent threonine/serine kinase family, is an endogenous photosensitizer, the overexpression of which in the epidermis increases the susceptibility of mice to UVR-induced cutaneous damage and development of squamous cell carcinoma. The PKCepsilon transgenic mouse (FVB/N) lines 224 and 215 overexpressed 8- and 18-fold PKCepsilon protein, respectively, over endogenous levels in basal epidermal cells. UVR exposure (1 kJ/m(2) three times weekly) induced irreparable skin damage in high PKCepsilon-overexpressing mouse line 215. However, the PKCepsilon transgenic mouse line 224, when exposed to UVR (2 kJ/m(2) three times weekly), exhibited minimum cutaneous damage but increased squamous cell carcinoma multiplicity by 3-fold and decreased tumor latency by 12 weeks. UVR exposure of PKCepsilon transgenic mice compared with wild-type littermates (1) elevated the levels of neither cyclobutane pyrimidine dimer nor pyrimidine (6-4) pyrimidone dimer, (2) reduced the appearance of sunburn cells, (3) induced extensive hyperplasia and increased the levels of mouse skin tumor promoter marker ornithine decarboxylase, and (4) elevated the levels of tumor necrosis factor alpha (TNFalpha) and other growth stimulatory cytokines, granulocyte colony-stimulating factor, and granulocyte macrophage colony-stimulating factor. The role of TNFalpha in UVR-induced cutaneous damage was evaluated using PKCepsilon transgenic mice deficient in TNFalpha. UVR treatment three times weekly for 13 weeks at 2 kJ/m(2) induced severe cutaneous damage in PKCepsilon transgenic mice (line 215), which was partially prevented in PKCepsilon-transgenic TNFalpha-knockout mice. Taken together, the results indicate that PKCepsilon signals UVR-induced TNFalpha release that is linked, at least in part, to the photosensitivity of PKCepsilon transgenic mice.
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Affiliation(s)
- Deric L Wheeler
- Department of Human Oncology, Medical School, University of Wisconsin, Madison, Wisconsin 53792, USA
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Higashi T, Yoshioka A, Shirakawa R, Tabuchi A, Nishioka H, Kita T, Horiuchi H. Direct demonstration of involvement of the adaptor protein ShcA in the regulation of Ca2+-induced platelet aggregation. Biochem Biophys Res Commun 2004; 322:700-4. [PMID: 15325286 DOI: 10.1016/j.bbrc.2004.07.177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Indexed: 10/26/2022]
Abstract
Platelet aggregation is mediated by conformational change of integrin alpha(IIb)beta(3). Tyrosine-phosphorylation of cytoplasmic domain of beta(3) upon platelet activation has been demonstrated to play a critical role in this process. Recently, the adaptor protein ShcA has been shown to bind to the tyrosine-phosphorylated beta(3), while it remains open whether ShcA plays any role in platelet aggregation. Here, we show that ShcA bound to tyrosine-phosphorylated beta(3)-tail peptide through its phosphotyrosine-binding domain in vitro. Then, we examined the involvement of ShcA in platelet aggregation by a previously established in vitro assay using platelets permeabilized with streptolysin-O, where exogenous addition of platelet cytosol is required for reconstitution of the Ca(2+)-induced aggregation. When ShcA was specifically depleted with anti-ShcA antibody from the cytosol, this ShcA-depleted cytosol lost the aggregation-supporting activity, which was rescued by addition of purified recombinant ShcA. Thus, ShcA is essential for the Ca(2+)-induced platelet aggregation.
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Affiliation(s)
- Tomohito Higashi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
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Stewart JR, O'Brian CA. Resveratrol antagonizes EGFR-dependent Erk1/2 activation in human androgen-independent prostate cancer cells with associated isozyme-selective PKC alpha inhibition. Invest New Drugs 2004; 22:107-17. [PMID: 14739659 DOI: 10.1023/b:drug.0000011787.75522.ec] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The development of androgen-independent prostate cancer (AI PrCa) involves constitutive Erk1/2 activation sustained by the epidermal growth factor/transforming growth factor-alpha/EGF receptor (EGF/TGFalpha/EGFR) axis and other trophic signaling mechanisms in neoplastic human prostate epithelial cells in vivo. In this report, we show that growth-inhibitory concentrations of the dietary phytochemical resveratrol suppress EGFR-dependent Erk1/2 activation pathways stimulated by EGF and phorbol ester (12- O -tetradecanoyl phorbol 13-acetate, TPA) in human AI PrCa PC-3 cells in vitro. Because protein kinase C (PKC) is the major cellular receptor for phorbol esters and taking into consideration that resveratrol is PKC-inhibitory, we investigated resveratrol effects on cellular PKC isozymes associated with the suppression of TPA-induced Erk1/2 activation. The PKC isozyme composition of PC-3 cells was defined by Western analysis of the cell lysate with a comprehensive set of isozyme-selective PKC Ab's. PC-3 cells expressed PKCalpha, epsilon, zeta, iota, and PKD (PKCmicro), as did another human AI PrCa cell line of distinct genetic origin, DU145. The effects of resveratrol on TPA-induced PKC isozyme activation were defined by monitoring PKC isozyme translocation and autophosphorylation. Under conditions where resveratrol suppressed TPA-induced Erk1/2 activation, the phytochemical produced isozyme-selective interference with TPA-induced translocation of cytosolic PKCalpha to the membrane/cytoskeleton and selectively diminished the amount of autophosphorylated PKCalpha in the membrane/cytoskeleton of the TPA-treated cells. These results demonstrate that resveratrol abrogation of a PKC-mediated Erk1/2 activation response in PC-3 cells correlates with isozyme-selective PKCalpha inhibition. The results provide evidence that resveratrol may have value as an adjuvant cancer therapeutic in advanced prostate cancer.
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Affiliation(s)
- Jubilee R Stewart
- Department of Cancer Biology, U.T.M.D. Anderson Cancer Center, Houston, TX 77030, USA
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Willis AI, Pierre-Paul D, Sumpio BE, Gahtan V. Vascular smooth muscle cell migration: current research and clinical implications. Vasc Endovascular Surg 2004; 38:11-23. [PMID: 14760473 DOI: 10.1177/153857440403800102] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Atherosclerosis and intimal hyperplasia are major causes of morbidity and mortality. These processes develop secondary to endothelial injury due to multiple stimuli, including smoking, diabetes mellitus, hypertension, and hyperlipidemia. Once this injury occurs, an essential element in the development of both these processes is vascular smooth muscle cell (VSMC) migration. Understanding the mechanisms involved in VSMC migration and ultimately the development of strategies by which this process can be inhibited, has been a major focus of research. The authors present a review of the extracellular proteins (growth factors, extracellular matrix components, and cell surface receptors) and intracellular signaling pathways involved in VSMC migration, as well as potential therapeutic approaches to inhibit this process.
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Affiliation(s)
- A I Willis
- Yale University School of Medicine, New Haven, CT, USA
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Alt A, Gartsbein M, Ohba M, Kuroki T, Tennenbaum T. Differential regulation of alpha6beta4 integrin by PKC isoforms in murine skin keratinocytes. Biochem Biophys Res Commun 2004; 314:17-23. [PMID: 14715240 DOI: 10.1016/j.bbrc.2003.12.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In mammalian epidermis, alpha6beta4 integrin is expressed exclusively on the basal layer localized to the hemidesmosomes, where it interacts extracellularly with the laminin-5 ligand. During differentiation, loss of alpha6beta4 is associated with keratinocyte detachment from the basement membrane and upward migration. The protein kinase C (PKC) family of isoforms participates in regulation of integrin function and is linked to skin differentiation. Exposure of primary murine keratinocytes to PKC activators specifically downregulates alpha6beta4 expression. Utilizing recombinant adenoviruses, we selectively overexpressed skin PKC isoforms in primary keratinocytes. PKCdelta and PKCzeta induced downregulation of alpha6beta4 protein expression, leading to reduced keratinocyte attachment to laminin-5 and enhanced gradual detachment from the underlying matrix. In contrast, PKCalpha upregulated alpha6beta4 protein expression, leading to increased keratinocyte attachment to laminin-5 and to the underlying matrix. Altogether, these results suggest distinct roles for specific PKC isoforms in alpha6beta4 functional regulation during the early stages of skin differentiation.
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Affiliation(s)
- Addy Alt
- Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
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Choudhury GG. A linear signal transduction pathway involving phosphatidylinositol 3-kinase, protein kinase Cepsilon, and MAPK in mesangial cells regulates interferon-gamma-induced STAT1alpha transcriptional activation. J Biol Chem 2004; 279:27399-409. [PMID: 15082710 DOI: 10.1074/jbc.m403530200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interferon-gamma (IFN-gamma) exerts an pleiotropic effect in mesangial cells in inflammatory glomerular diseases. The biologic effect of IFN-gamma is mediated by STAT1alpha. The precise mechanism by which IFN-gamma stimulates the transcriptional activity of STAT1alpha is poorly understood. I investigated the role of protein kinase C (PKC) epsilon in regulating the transcriptional activation of STAT1alpha in mesangial cells. IFN-gamma increased PKCepsilon activity in a time-dependent manner with a concomitant increase in STAT1alpha transcriptional activity. Expression of constitutively active PKCepsilon mimicked the effect of IFN-gamma on STAT1alpha-dependent transcription. Expression of dominant negative PKCepsilon inhibited IFN-gamma-induced STAT1alpha-dependent transcription. Ly294002, a pharmacological inhibitor of phosphatidylinositol (PI) 3-kinase, blocked IFN-gamma-induced PKCepsilon activity and resulted in inhibition of STAT1alpha transcriptional activity but had no effect on STAT1alpha tyrosine phosphorylation and STAT1alpha-DNA complex formation. A PKC inhibitor, H7, also had no effect on STAT1alpha tyrosine phosphorylation and DNA binding. However, Ly294002 and H7 blocked IFN-gamma-induced serine phosphorylation of STAT1alpha. These data indicate that PI 3 kinase-dependent PKCepsilon regulates STAT1alpha transcriptional activity in the absence of any effect on its DNA binding capability. In addition to activating PKCepsilon, IFN-gamma increased MAPK activity, resulting in transcriptional activation of Elk-1, a nuclear target of MAPK. Ly294002 or a dominant negative PI 3-kinase significantly blocked IFN-gamma-induced MAPK activity. On the other hand, ectopic expression of constitutively active PKCepsilon significantly increased MAPK activity. IFN-gamma-stimulated MAPK phosphorylated STAT1alpha in vitro. Inhibition of MAPK activity blocked IFN-gamma-induced serine phosphorylation of STAT1alpha; but its tyrosine phosphorylation and DNA binding were partially inhibited. Finally, expression of dominant negative MAPK significantly inhibited IFN-gamma-induced STAT1alpha-dependent transcription. These data provide the first evidence that IFN-gamma stimulates PKCepsilon in a PI 3-kinase-sensitive manner to activate MAPK, which regulates STAT1alpha transcriptional activity.
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Affiliation(s)
- Goutam Ghosh Choudhury
- Department of Medicine, University of Texas Health Science Center at San Antonio, 78229-3900, USA
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41
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Hsu MJ, Lin WW, Tsao WC, Chang YC, Hsu TL, Chiu AW, Chio CC, Hsieh SL. Enhanced adhesion of monocytes via reverse signaling triggered by decoy receptor 3. Exp Cell Res 2004; 292:241-51. [PMID: 14697332 DOI: 10.1016/j.yexcr.2003.09.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Decoy receptor 3 (DcR3), a newly identified soluble protein belonging to the tumor necrosis factor receptor (TNFR) superfamily, is a receptor for Fas ligand (FasL), LIGHT and TL1A. It has been demonstrated that DcR3 is frequently overexpressed by malignant tumors arising from lung, gastrointestinal tract, neuronal glia and virus-associated leukemia. Recently, we demonstrated that DcR3 is able to modulate the differentiation and activation of dendritic cells (DCs), and that DcR3-treated DCs skew naive T cell differentiation towards a Th2 phenotype. In this study, we further demonstrate that DcR3 is able to induce actin reorganization and enhance the adhesion of monocytes and THP-1 cells by activating multiple signaling molecules, such as protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), focal adhesion kinase (FAK) and Src kinases. This provides the first evidence that the soluble DcR3, like other immobilized members of TNFR superfamily, is able to trigger 'reverse signaling' to modulate cell function.
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Affiliation(s)
- Ming-Jen Hsu
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Anilkumar N, Parsons M, Monk R, Ng T, Adams JC. Interaction of fascin and protein kinase Calpha: a novel intersection in cell adhesion and motility. EMBO J 2004; 22:5390-402. [PMID: 14532112 PMCID: PMC213775 DOI: 10.1093/emboj/cdg521] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Coordination of protrusive and contractile cell-matrix contacts is important for cell adhesion and migration, but the mechanisms involved are not well understood. We report an unexpected direct association between fascin, an actin-bundling component of filopodia, microspikes and lamellipodial ribs, and protein kinase Calpha (PKCalpha), a regulator of focal adhesions. The association is detectable by protein-protein binding in vitro, by coimmunoprecipitation from cell extracts, and in live cells as fluorescence resonance energy transfer detected by fluorescence imaging lifetime microscopy. The interaction is physiologically regulated by the extracellular matrix context of cells, depends on activation of PKCalpha and is mediated by the C1B domain of PKCalpha. Strikingly, a fascin mutant, fascin S39D, associates constitutively with PKCalpha. Through use of a newly developed set of membrane-permeable peptides that separately inhibit either fascin/PKCalpha or fascin/actin binding, we have uncovered that specific blockade of the fascin/PKCalpha interaction increases cell migration on fibronectin in conjunction with increased fascin protrusions and remodeling of focal adhesions. These results identify the fascin-PKCalpha interaction as an important novel intersection in the regulation and networking of cell-matrix contacts.
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Affiliation(s)
- N Anilkumar
- MRC Laboratory for Molecular Cell Biology and Department of Biochemistry and Molecular Biology, University College London, London WC1E 6BT, UK
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Asghar M, Hussain T, Lokhandwala MF. Overexpression of PKC-betaI and -delta contributes to higher PKC activity in the proximal tubules of old Fischer 344 rats. Am J Physiol Renal Physiol 2003; 285:F1100-7. [PMID: 12904329 DOI: 10.1152/ajprenal.00198.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previously, we reported that natriuretic and diuretic response to dopamine is diminished in old Fischer 344 rats, which is due to higher basal protein kinase C (PKC) activity and hyperphosphorylation of Na-K-ATPase in the proximal tubules (PTs) of old rats. The present study was conducted to determine whether higher PKC activity could be due to altered expression of some of the PKC isoforms in the superficial cortex (rich in PTs) of old rats. Fluorimetric measurement showed almost twofold increase in the PKC activities in homogenates and membranes of old (24 mo) compared with adult (6 mo) rats. Interestingly, in the basal state PKC-betaI was overexpressed in the membranes, whereas PKC-delta expression was increased in the cytosol of old compared with adult rats. Treatment of the cortical slices with either SKF-38393, a D1-like agonist, or PDBu, a direct activator of PKC, caused translocation of PKC-betaI from cytosol to membranes in adult but not in old rats. Both of these drugs caused translocation of PKC-delta from membranes to cytosol in adult but not in old rats. These drugs had no effect on translocation of PKC-zeta in both adult and old rats. Both PKC-betaI and -delta co-immunoprecipitated with alpha1-subunit of Na-K-ATPase in adult and old rats. These observations suggest that both SKF-38393 and PDBu differentially regulate PKC-betaI and -delta in adult but not in old rats. Also, PKC-betaI and -delta seem to interact with Na-K-ATPase in these animals. The overexpression of both PKC-betaI and -delta in old rats could be responsible for a higher basal PKC activity, which causes the hyperphosphorylation of Na-K-ATPase and contributes to the diminished inhibition of Na-K-ATPase activity by dopamine in old rats.
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Affiliation(s)
- Mohammad Asghar
- Heart and Kidney Institute, College of Pharmacy, University of Houston, Houston, TX 77204, USA
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Davis MI, Ronesi J, Lovinger DM. A Predominant Role for Inhibition of the Adenylate Cyclase/Protein Kinase A Pathway in ERK Activation by Cannabinoid Receptor 1 in N1E-115 Neuroblastoma Cells. J Biol Chem 2003; 278:48973-80. [PMID: 14517212 DOI: 10.1074/jbc.m305697200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cannabinoids activate several members of the mitogen-activated protein kinase superfamily including p44 and p42 extracellular signal-regulated kinase (ERK). We used N1E-115 neuroblastoma cells and the cannabinoid receptor agonist WIN 55,212-2 (WIN) to examine the signal transduction pathways leading to the activation of ERK. ERK phosphorylation (activation) was measured by Western blot. The EC50 for stimulation of ERK phosphorylation was 10 nm, and this effect was blocked by pertussis toxin and the CB1 (cannabinoid) receptor antagonist SR141716A. The MEK inhibitors PD 98059 and U0126 blocked ERK phosphorylation, as did the adenylate cyclase activator forskolin. The phosphatidylinositol (PI) 3-kinase inhibitor LY 294002 and the Src kinase inhibitor PP2 partially occluded the response but also decreased basal levels of phospho-ERK. The PI 3-kinase and Src pathways are known to promote cell survival in many systems; therefore, MTT (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan) conversion was used to examine the effects of these inhibitors on cellular viability. LY 294002 decreased the number of viable cells after 18 h of treatment; therefore, the inhibition of ERK by this inhibitor is probably because of cytotoxicity. Forskolin blocked ERK phosphorylation with an EC50 of <3 microm, and the protein kinase A (PKA) inhibitor H-89 enhanced ERK phosphorylation. c-Raf phosphorylation at an inhibitory PKA-regulated site (Ser259) was also reduced by WIN. This is probably due to constitutive phosphatase activity because WIN did not directly stimulate PP1 or PP2A activity when measured using 6,8-difluoro-4-methylumbelliferyl phosphate as a fluorogenic substrate. These data implicate the inhibition of PKA as the predominant pathway for ERK activation by CB1 receptors in N1E-115 cells. PI 3-kinase and Src appear to contribute to ERK activation by maintaining activation of kinases, which prime the pathway and maintain cellular viability.
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Affiliation(s)
- Margaret I Davis
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, Maryland 20852, USA.
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45
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Xie Z, Singh M, Siwik DA, Joyner WL, Singh K. Osteopontin inhibits interleukin-1beta-stimulated increases in matrix metalloproteinase activity in adult rat cardiac fibroblasts: role of protein kinase C-zeta. J Biol Chem 2003; 278:48546-52. [PMID: 14500723 DOI: 10.1074/jbc.m302727200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have shown that osteopontin (OPN), an extracellular matrix protein, plays an important role in post myocardial infarction (MI) remodeling by promoting collagen synthesis and accumulation. Interleukin-1beta (IL-1beta), increased in the heart following MI, increases matrix metalloproteinase (MMP) activity in cardiac fibroblasts in vitro. Here, we show that OPN alone has no effect on MMP activity or expression. However, it reduces IL-1beta-stimulated increases in MMP activity and expression in adult rat cardiac fibroblasts. Pretreatment with bovine serum albumin had no effect on MMP activity or protein content, whereas GRGDS (glycine-arginine-glycine-aspartic acid-serine)-pentapeptide (which interrupts binding of RGD-containing proteins to cell surface integrins) and monoclonal antibody m7E3 (a rat beta3 integrins antagonist) inhibited the effects of OPN. Inhibition of PKC using chelerythrine inhibited the activities of both MMP-2 and MMP-9. Stimulation of cells using IL-1beta increased phosphorylation and translocation of PKC to membrane fractions, which was inhibited by OPN. OPN inhibited IL-1beta-stimulated increases in translocation of PKC-zeta from cytosolic to membrane fractions. Furthermore, the levels of phospho-PKC-zeta were lower in the cytosolic fractions of OPN knock-out mice hearts as compared with wild type 6 days post-MI. Inhibition of PKC-zeta using PKC-zeta pseudosubstrate inhibited IL-1beta-stimulated increases in MMP-2 and MMP-9 activities. These observations suggest that OPN, acting via beta3 integrins, inhibits IL-1beta-stimulated increases in MMP-2 and MMP-9 activity, at least in part, via the involvement of PKC-zeta. Thus, OPN may play a key role in collagen deposition during myocardial remodeling following MI by modulating cytokine-stimulated MMP activity.
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Affiliation(s)
- Zhonglin Xie
- Department of Physiology, James H Quillen College of Medicine, James H. Quillen Veterans Affairs Medical Center, East Tennessee State University, Johnson City, Tennessee 37614, USA
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Cho JY, Katz DR, Chain BM. Staurosporine induces rapid homotypic intercellular adhesion of U937 cells via multiple kinase activation. Br J Pharmacol 2003; 140:269-76. [PMID: 12970105 PMCID: PMC1574032 DOI: 10.1038/sj.bjp.0705436] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Staurosporine is a broad-specificity kinase inhibitor, which has acted as lead compound for the development of some novel cytotoxic compounds for treatment of cancer. This study investigates the unexpected observation that staurosporine can also induce homotypic cellular aggregation. 2. In this study, staurosporine is shown to activate rapid homotypic aggregation of U937 cells, at concentrations below those required to induce cell death. This activity is a particular feature of staurosporine, and is not shared by a number of other kinase inhibitors. The proaggregating activity of staurosporine is inhibited by deoxyglucose, cytochalasin B and colchicine. Staurosporine-induced aggregation can be distinguished from that induced by the phorbol 12-myristate 13-acetate by faster kinetics and insensitivity to cycloheximide. Staurosporine induces translocation of conventional and novel, but not atypical isoforms of protein kinase C (PKC). Aggregation induced by staurosporine is inhibited by a number of inhibitors of PKC isoforms, and by inhibitors of protein tyrosine kinases. Staurosporine also induces rapid phosphorylation of ERK and p38, and inhibitors of both these enzymes block aggregation. 3. Staurosporine induces dysregulated activation of multiple kinase signaling pathways in U937 cells, and the combined activity of several of these pathways is essential for the induction of aggregation.
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Affiliation(s)
- Jae Youl Cho
- Department of Immunology and Molecular Pathology, Windeyer Institute of Medical Sciences, University College London, 46 Cleveland Street, London W1T 4JF
| | - David R Katz
- Department of Immunology and Molecular Pathology, Windeyer Institute of Medical Sciences, University College London, 46 Cleveland Street, London W1T 4JF
| | - Benjamin M Chain
- Department of Immunology and Molecular Pathology, Windeyer Institute of Medical Sciences, University College London, 46 Cleveland Street, London W1T 4JF
- Author for correspondence:
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Merighi S, Baraldi PG, Gessi S, Iannotta V, Klotz KN, Leung E, Mirandola P, Tabrizi MA, Varani K, Borea PA. Adenosine receptors and human melanoma. Drug Dev Res 2003. [DOI: 10.1002/ddr.10181] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Cho JY, Skubitz KM, Katz DR, Chain BM. CD98-dependent homotypic aggregation is associated with translocation of protein kinase Cdelta and activation of mitogen-activated protein kinases. Exp Cell Res 2003; 286:1-11. [PMID: 12729789 DOI: 10.1016/s0014-4827(03)00106-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
CD98 is a protein found on the surface of many activated cell types, and is implicated in the regulation of cellular differentiation, adhesion, growth, and apoptosis. Despite many studies addressing CD98 function, there is little information on the intracellular signalling pathways that mediate its activity. In this study, we examine protein kinase pathways that are activated following ligation by the CD98 antibody AHN-18, an antibody that induces U937 homotypic aggregation and inhibits antigen presenting activity and T-cell activation. Ligation by CD98 antibody AHN-18 induces tyrosine kinase activity, but inhibition of this activity does not affect U937 aggregation. Ligation also induces membrane translocation of the serine/threonine kinase novel PKCdelta, but not other members of the PKC family. Translocation is blocked by rottlerin, and this inhibitor also blocks aggregation. PKCdelta activation in turn mediates activation of ERK1/2 and p38, as well as tyrosine phosphorylation of multiple proteins, and MAPK activation is essential for cellular aggregation. One of the targets of CD98-induced tyrosine phosphorylation is itself PKCdelta, suggesting that this phosphorylation may act as a negative feedback to limit the overall activation of the CD98 pathway.
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Affiliation(s)
- Jae Youl Cho
- Department of Immunology and Molecular Pathology, Windeyer Institute of Medical Sciences, University College London, 46 Cleveland Street, London W1T 6JF, UK
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Shirasawa Y, Rutland TJ, Young JL, Dean DA, Benoit JN. Modulation of protein kinase C (PKC)-mediated contraction and the possible role of PKC epsilon in rat mesenteric arteries. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2003; 8:a133-8. [PMID: 12700091 PMCID: PMC4400799 DOI: 10.2741/1087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
he involvement of protein kinase C (PKC) in isometric tension development of rat mesenteric arteries was investigated. Non-selective inhibition of PKC and selective inhibition of the epsilon isoform were performed using the PKC inhibitor, chelerythrine, and non-viral gene-transfer of a kinase inactive mutant of PKCepsilon (PKCepsilon-KN), respectively. Chelerythrine (2.5 or 5.0 microM) significantly and equally attenuated phenylephrine-induced but not potassium-induced contractions. Higher concentrations of chelerythrine (10 microM) caused the vessels to lose responsiveness to both phenylephrine and potassium chloride. Transfection of blood vessels with epsilon-KN also resulted in significant attenuation of contractile responses to phenylephrine. Potassium chloride-induced responses were not altered in transfected arteries. In a separate group of vessels, the relationship between [Ca2+]i and isometric tension was evaluated. These studies suggested that calcium sensitivity of the contractile apparatus was decreased in vessels when PKC-epsilon activity was compromised. The results of the study suggest that PKC-epsilon can modulate phenylephrine-induced contraction in mesenteric arteries via calcium-independent pathways.
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Affiliation(s)
- Yuichi Shirasawa
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, Grand Forks, North Dakota
| | - Travis J. Rutland
- Department of Physiology, University of South Alabama College of Medicine, Mobile, Alabama
| | - Jennifer L. Young
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois
| | - David A. Dean
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois
| | - Joseph N. Benoit
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, Grand Forks, North Dakota
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Gallet C, Blaie S, Lévy-Toledano S, Habib A. Epidermal-growth-factor receptor and metalloproteinases mediate thromboxane A2-dependent extracellular-signal-regulated kinase activation. Biochem J 2003; 371:733-42. [PMID: 12534349 PMCID: PMC1223323 DOI: 10.1042/bj20021030] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2002] [Revised: 01/17/2003] [Accepted: 01/21/2003] [Indexed: 11/17/2022]
Abstract
The signalling pathways that link G-protein-coupled receptors to mitogen-activated protein kinases involve receptor and non-receptor tyrosine kinases and protein kinase C (PKC). We explored the pathways that are implicated in the thromboxane (TX) A(2)-dependent activation of extracellular-signal-regulated protein kinase (ERK) and the role of the two TX receptor (TP) isoforms, TP alpha and TP beta. ERK activation by IBOP, a TX analogue, was dependent on epidermal-growth-factor receptor (EGFR) in TP alpha- or TP beta-transfected cells and in human aortic smooth muscle cells (hASMCs), since AG1478, a selective inhibitor of tyrosine phosphorylation of the EGFR, strongly blocked ERK and EGFR phosphorylation. In addition, EGFR transactivation leading to ERK activation involved matrix metalloproteinases (MMPs), since BB2516, an inhibitor of MMP, decreased ERK and EGFR phosphorylation in TP alpha- or TP beta-transfected cells. Moreover, we showed that both isoforms activate ERK phosphorylation in an Src-kinase-dependent manner, whereas PKC was mainly implicated in ERK activation and EGFR phosphorylation by TP beta. In hASMCs, we showed that ERK activation depended on both pertussis-sensitive and -insensitive G alpha-proteins. We demonstrated further that EGFRs, PKC, Src kinase and MMPs are involved in ERK activation by TX. The results of the present study highlight a role for MMPs and PKC in EGFR transactivation triggered by the TPs and demonstrate this mechanism for the first time in primary cells, i.e. hASMCs.
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Affiliation(s)
- Carole Gallet
- INSERM U348, Institut Fédératif 6-Circulation-Paris 7,8 rue Guy Patin, Hôpital Lariboisière, 75010 Paris Cedex, France
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